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4 years ago

Solve the simultaneous equations 3x+y=8 X-3Y=11

Mathematics

2 answers:

vlabodo [156]4 years ago

6 0

Answer:

Step-by-step explanation:

let's organize our information :

3x+y=8
x-3y=11

The trick here is to multiply x-3y=11 by -3 then add it to 3x+y=8 to get rid of x and get a normal equation

we get : -3x+9y= (-33)

then after the addition : 3x+y-3x+9y=8-33⇔ 10y=(-25)

so y=(-25)/10= -5/2

let's replace y by -5/2 in 3x+y=8
3x-5/2 =8⇔ x= 21/6

so y= (-5/2) and x= 21/6

Gala2k [10]4 years ago

3 0

Answer:

(7/2, -5/2)

Step-by-step explanation:

We can solve this multiple ways: Algebraically (Substitution or Elimination) or Graphically

Step 1: Write 1st equation in terms of y

y = 8 - 3x

Step 2: Substitute y of 2nd equation

x - 3(8 - 3x) = 11

Step 3: Solve for x

x - 24 + 9x = 11

10x - 24 = 11

10x = 35

x = 7/2

Step 4: Plug x to find y

3(7/2) + y = 8

21/2 + y = 8

y = -5/2

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Which of the following is not an ordered pair from the function f(x) = 5x - 6?

DerKrebs [107]

We have been given a function $f(x) = 5x - 6$ . We are asked to choose the point from given choices, which is not a solution of given function.

Let us check each given point one by one.

A. (3,9)

$f(x) = 5x - 6$

$9= 5(3)-6$

$9=15-6$

$9=9$

Since both sides of function are equal, therefore, point (3,9) is the solution of our given function.

B. $(1,-1)$

$f(x) = 5x - 6$

$-1= 5(1)-6$

$-1= 5-6$

$-1=-1$

Since both sides of function are equal, therefore, point $(1,-1)$ is the solution of our given function.

C. $(5,19)$

$f(x) = 5x - 6$

$19= 5(5)-6$

$19= 25-6$

$19=19$

Since both sides of function are equal, therefore, point $(5,19)$ is the solution of our given function.

D. $(4,10)$

$f(x) = 5x - 6$

$10= 5(4)-6$

$10= 20-6$

$10\neq 14$

Since both sides of function are not equal, therefore, point $(4,10)$ is not a solution of our given function and option D is the correct choice.

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4 years ago

Which is a solution to (x – 3)(x + 9) = –27? x = –9 x = –3 x = 0 x = 6

likoan [24]

Answer:

x = 0

Step-by-step explanation:

Since the product is not equal zero, we need to multiply both parenthesis first:

$(x-3)(x+9) =-27$

$x*x+x*9+(-3)*x+(-3)*9=27$

$x^2+9x-3x-27=27$

$x^2+6x-27=27$

Add 27 from both sides:

$x^2+6x-27+27=-27+27$

$x^2-6x=0$

Factor $x$ out:

$x(x+6)=0$

Apply the zero product:

$x=0,x+6=0$

$x=0,x=-6$

The solutions of the equation are $x=0$ and $x=-6$ .

We can conclude that the correct answer is x = 0.

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3 years ago

How many cups of sorbet are used in. 8 cups of punch sorbet is 15%

MariettaO [177]

15% * 8 cups
= 0.15 * 8 cups
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3 years ago

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This number is in scientific notation. 2. 4 × 10-4 Convert the number into standard notation. What is the value? 2. 4 × 10-4 =.

Dimas [21]

2.4x10^-4 = 0.00024

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2 years ago

Each interior angle of a regular n-sided polygon is 150 degrees. How many sides does the polygon have?

notsponge [240]

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Divide each side by 30 :

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3 years ago